The present invention relates to printing presses in general, and more particularly to improvements in means for positioning or locating the printing cylinder in the frame of a rotary printing press.
As a rule, the end portions of the printing cylinder in a rotary printing press are carried by arms which are movably mounted on the corresponding uprights of the machine frame. The arms are pivotable to and from their operative (normally horizontal) positions and can be locked in the operative positions. The printing cylinder can be lifted off or deposited onto the arms upon completion of several preliminary operations involving detachment of the cylinder from certain parts of the press and rolling the end portions of the cylinder along and toward the free end portions of the respective arms. When the cylinder reaches a predetermined position, the antifriction bearings which are carried by its stubs can be detached and the detached bearings are then deposited on suitable supports which are provided in the frame of the printing press adjacent to the stubs in the predetermined position of the cylinder. The rolling movement is thereupon resumed so that the stubs of the cylinder reach the end portions of the respective arms and can be lifted by a wheel-mounted elevator or the like.
The mounting of a fresh printing cylinder in the frame of a rotary printing press involves the placing of stubs onto the free end portions of the arms so that the stubs can begin to roll along the generally horizontal supporting surfaces of the arms. The rolling movement is interrupted when the cylinder reaches its predetermined position in which the stubs are properly aligned with the respective antifriction (e.g., ball) bearings. When the assembly of bearings with the stubs is completed, the cylinder is again set in rolling motion so as to advance toward and to assume its operative position.
It is desirable and important to properly locate the printing cylinder in the aforementioned predetermined position so as to ensure that the bearings can be readily and predictably slipped into or detached from the respective stubs. Moreover, the means for holding the cylinder in its predetermined position must be designed in such a way that it allows for practically unobstructed and smooth advancement of the cylinder toward as well as away from this position. Furthermore, it is important to ensure that the movement of the cylinder to and from its predetermined position should be completed within short intervals of time.
Heretofore known proposals to facilitate movements of the printing cylinder to and from its predetermined position include the provision of two levers each of which is pivotable relative to the corresponding arm and defines a socket for reception of the adjacent stub when the cylinder reaches that (predetermined) position in which the bearings can be readily mounted on or detached from the respective stubs. The levers cooperate with means for releasably blocking them in selected positions, and the levers are mounted on a guide rail so as to enable them to assume a plurality of different positions, i.e., the printing cylinder can be arrested and held in a selected one of several positions at different distances from the operative position. A drawback of such proposal is that the levers must be manipulated by hand, not only to enable them to block the movements of a cylinder from its operative position but also to shift the levers with or relative to the guide rail so as to select that position of the cylinder in which the bearings can be readily mounted on or detached from the respective stubs.
Another drawback of the just discussed proposal is that the means for mounting the levers is disposed between the head end of the cylinder and an inner wall of the lateral upright of the machine frame. Any manipulation by hand can entail injury to the operator. Still another drawback of such proposal is that, if the setting of the blocking means for the levers is improper, the cylinder cannot be rolled and/or otherwise manipulated which can bring about extensive lengthening of the intervals of manipulation of the cylinder, either for the purpose of removing it from or for the purpose of installing it in the frame of a rotary printing press or a like machine.